1,693 research outputs found

    Challenges to smartphone applications for melanoma detection

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    This commentary addresses the emerging market for health-related smartphone applications. Specific to dermatology, there has been a significant increase not only in applications that promote skin cancer awareness and education but also in those meant for detection. With evidence showing that 365 dermatology-related applications were available in 2014--up from 230 in 2012--and that 1 in 5 patients under the age of 50 have used a smartphone to help diagnose a skin problem, there is clearly a large subset of patients participating in this growing trend. Therefore, we are obligated to take a closer look into this phenomenon. Studies have shown that applications are inferior to in-person consultations with one study showing that 3 out of 4 applications incorrectly classified 30% or more melanomas as low-risk lesions. Although the FDA gained regulatory oversight over mobile health applications in 2012 and recently released their statement in 2015, their reach only extends to cover a selected portion of these applications, leaving many unregulated as they continue to be marketed toward our patients. Dermatologists should be updated on our current situation in order to properly counsel patients on the risks and benefits of these applications and whether they are acceptable for use. © 2016 by the article author(s)

    Precision Drought Stress in Orchards: Rootstock Evaluation, Trunk Hydration and Canopy Temperature

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    In many areas, over half of all diverted water is used for irrigation. Tree fruit crops use a lot of water, but water productivity can be increased using properly-timed precision water stress. In addition to water conservation, increases in water productivity arise from better fruit quality, increased storage life and reductions in pruning and maintenance. One major hurdle to applying precision water stress in orchards is the lack of a reliable, automated method of determining tree water status. However, the influence of physiological characteristics such as rootstock vigor on water productivity are also important. Selecting the most appropriate rootstocks and accurately determining the water status of orchard trees can increase water productivity. Research has shown that some rootstocks can more effectively extract water from soil. In this research, the response to water stress of three different Gisela tart cherry dwarfing rootstocks was compared using a weighing lysimeter system. Gisela 12 and Gisela 3 rootstocks recovered from drought stress more quickly and had higher trunk diameter growth rates than drought-stressed Gisela 5 rootstocks. Two potential methods of determining tree water status were also evaluated. Trunk hydration was measured using electromagnetic sensors and canopy temperature changes were detected using infrared radiometry. Electromagnetic techniques, including time domain reflectometry, can be used to determine the water content of wood. Until recently, the cost of this technology has inhibited its widespread use, but new affordable commercial electromagnetic soil moisture sensors have created renewed interest in this technique. In this research five different types of electromagnetic soil moisture sensors were inserted into the trunks of fruit trees and were monitored over two growing seasons. Maximizing exposure of waveguides to the sapwood increased the response of these sensors to changes in stem water potential. Infrared measurements of canopy temperature have successfully been used with field crops. However, the heterogeneity of orchard canopies makes this technique more difficult in orchards. Here, the efficacy of aiming radiometers at single trees versus at entire orchards was compared over multiple growing seasons. Neither single tree measurements nor whole orchard techniques produced a sufficiently robust signal to recommend them for general use

    Effects of Counselor-Subject Value Congruence on Willingness to Self-Disclose in an Analogue Psychotherapy Interview Situation

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    A substantial amount of research has been directed towards identifying particular factors which contribute toward a positive psychotherapy outcome. One variable which appears to positively influence psychotherapy outcome is the therapeutic alliance, or the establishment of a positive working relationship between client and counselor. The present study investigated the therapeutic alliance as a function of the degree of agreement between client and therapist about Affective Control values, or beliefs concerning whether emotional expression constitutes healthy or unhealthy emotional adjustment. Subjects consisted of 111 undergraduate students; 64 subjects were identified as high scorers on the Affective Control Scale of the Mental Health Values Questionnaire (MHVQ), and 47 were identified as low scorers. Half of the high and low score subjects were exposed to a therapist on videotape who described affective control as a positive indicator of emotional adjustment (i.e., high on Affective Control). The other half of high and low score subjects were exposed to a therapist on videotape who described affective control as a negative indicator of emotional adjustment (i.e., low on Affective Control). Thus, half of all subjects experienced a therapist-value congruent condition while the remaining subjects experienced a therapist-value incongruent condition. Results indicated that therapist-value congruent subjects rated the therapist as both more trustworthy and more comfortable to be with than did incongruent subjects. An unhypothesized finding indicated that high affective control-score subjects rated the therapist more positively on a number of traits than did low affective control-score subjects. It is possible that the more positive ratings by high affective control-score subjects may be a function of a general reserve or reluctance to express openly negative opinions about others, thus resulting in inflated therapist evaluations. However, it is also possible that the Affective Control Scale of the MHVQ may actually be measuring a variable other than affective control values, such as a Positive Outlook or Positive Appraisal Tendency. Further research utilizing the MHVQ will contribute to our understanding of the factors which are involved in a successful therapeutic alliance

    Interpreting the Evidence on Life Cycle Skill Formation

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    This paper presents economic models of child development that capture the essence of recent findings from the empirical literature on skill formation. The goal of this essay is to provide a theoretical framework for interpreting the evidence from a vast empirical literature, for guiding the next generation of empirical studies, and for formulating policy. Central to our analysis is the concept that childhood has more than one stage. We formalize the concepts of self-productivity and complementarity of human capital investments and use them to explain the evidence on skill formation. Together, they explain why skill begets skill through a multiplier process. Skill formation is a life cycle process. It starts in the womb and goes on throughout life. Families play a role in this process that is far more important than the role of schools. There are multiple skills and multiple abilities that are important for adult success. Abilities are both inherited and created, and the traditional debate about nature versus nurture is scientifically obsolete. Human capital investment exhibits both self-productivity and complementarity. Skill attainment at one stage of the life cycle raises skill attainment at later stages of the life cycle (self-productivity). Early investment facilitates the productivity of later investment (complementarity). Early investments are not productive if they are not followed up by later investments (another aspect of complementarity). This complementarity explains why there is no equity-efficiency trade-off. for early investment. The returns to investing early in the life cycle are high. Remediation of inadequate early investments is difficult and very costly as a consequence of both self-productivity and complementarity.

    Diagonalizing operators over continuous fields of C*-algebras

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    It is well known that in the commutative case, i.e. for A=C(X)A=C(X) being a commutative C*-algebra, compact selfadjoint operators acting on the Hilbert C*-module HAH_A (= continuous families of such operators K(x)K(x), x∈Xx\in X) can be diagonalized if we pass to a bigger W*-algebra L∞(X)=A⊃AL^\infty(X)={\bf A} \supset A which can be obtained from AA by completing it with respect to the weak topology. Unlike the "eigenvectors", which have coordinates from A\bf A, the "eigenvalues" are continuous, i.e. lie in the C*-algebra AA. We discuss here the non-commutative analog of this well-known fact. Here the "eigenvalues" are defined not uniquely but in some cases they can also be taken from the initial C*-algebra instead of the bigger W*-algebra. We prove here that such is the case for some continuous fields of real rank zero C*-algebras over a one-dimensional manifold and give an example of a C*-algebra AA for which the "eigenvalues" cannot be chosen from AA, i.e. are discontinuous. The main point of the proof is connected with a problem on almost commuting operators. We prove that for some C*-algebras if h∈Ah\in A is a selfadjoint, u∈Au\in A is a unitary and if the norm of their commutant [u,h][u,h] is small enough then one can connect uu with the unity by a path u(t)u(t) so that the norm of [u(t),h][u(t),h] would be also small along this path.Comment: 21 pages, LaTeX 2.09, no figure

    Quantifying Tree Hydration Using Electromagnetic Sensors

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    An automated method of determining tree water status would enable tree fruit growers, foresters and arborists to reduce water consumption, reduce orchard maintenance costs and improve fruit quality. Automated measurements could also be used to irrigate based on need rather than on fixed schedules. Numerous automated approaches have been studied; all are difficult to implement. Electromagnetic sensors that measure volumetric water content can be inserted in tree trunks to determine relative changes in tree water status. We performed automated measurements of dielectric permittivity using four commercially available electromagnetic sensors in fruit tree trunks over the 2016 growing season. These sensors accurately measure the ratio of air and water in soils, but tree trunks have minimal air-filled porosity. The sensors do respond, however, to bound and unbound water and the relative change in the output of the sensors thus provides an indication of this ratio. Sapwood is the hydro-dynamically responsive component of trunk anatomy and is nearest the bark. Sensor response improved when the waveguides were exposed to a greater percentage of sapwood. Irrigation-induced increases of approximately 0.5 MPa in stem water potential were associated with 0.5 unit increases in dielectric permittivity. Electromagnetic sensors respond to bound water in trees and thus have the potential to indicate tree water status, especially when the sensor rods are in contact with sapwood. Sensor modifications and/or innovative installation techniques could enable automated measurements of tree water status that could be used to precision irrigate trees
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